Metal blank and method of blanking



y 1941- R. H. MADDOCK 2,250,641

METAL BLANK AND METHOD OF BLANKING Original Filed Nov. 26, 1958 I NEWFORM SHEET INVENTOR. ROBERT H. MADDOCK.

01.0 FORM SHEET 2 F|G.2

Patented July 29, 1941 .METAL BLANK AND BIETHOD OF BLANKING Robert H.Maddock, Lakewood, Ohio, assignor to The Midland Steel Products Company,Cleveland, Ohio, a corporation of Ohio Original application November 26,1938, Serial" No. 242,554. Divided and thisapplication January 23, 1941,Serial No. 375,647

6 Claims. (01. 16 1-17) This invention relates to new and usefulimprovements in sheet metal blanking and is a division of applicationSerial No. 242,554 filed November 26, 1938.

An important object of the invention is to provide special shaped sheetsteel stock and a method of laying out special blanks or pieces thereon,which results in obtaining a greater number of such pieces per ton ofsheets than can be obtained by blanking the pieces from the usualrectangular sheets heretofore supplied by the steel industry.

Other objects and advantages of the invention will become apparentduring the course of the following description.

In the accompanying drawing. forming a part of the application andwherein like numerals are employed to designate like parts throughoutthe several views- Fig. 1 is a plan of the new form of sheet illus--trating one manner of nesting and blanking subrails of automobile framestherefrom and,

Fig. 2 is a plan of the old form of rectangularsheet illustratingapplicants improved manner of nesting these special blanks thereon.

In order to appreciate the economies derived from the special form ofsheet and blanking disclosed herein, prior practice must be understood.In the case of sheet steel ordered by companies which manufactureautomobile frames or parts thereof having longitudinal co-planar bendsor offsets to lower the center of gravity of the frame, it has been thepractice to purchase rectangular sheets I of Fig. 2 under 46, 60 and 72inches in width, since this has been the and any sheets exceeding thesewidth sell for premium prices. Therefore, the fabricatingcompanies makeit their practice in ordering sheet. steel for this purpose, to order.sheets as much below the premium priced sheets as are commensurate withobtaining the largest number of rail or sub-rail blanks per-ton-cost, ofsteel ordered. These blanks usually each average 6 to 12 inches wide andfrom to 15 feet long. In addition, the sub-rails have one co-planarofiset or kickup portion 2, while the main rails usually possess two ofsuch kickup portions. Thus, these blanks are of generally elongated,somewhat serpentine form, and being tapered in addition, makeseconomical blanking quite a huge cost problem when hundreds of thousandsof these blanks are involved.

In the case of sub-rail blanks B as shown in the drawing, which taperfrom a wide end 4 and cause greater spacing of the blanks inthese 3 onlyshape in which steel mills furnish this stock the individual blanks to aminimum, it obviously down to a narrow kickup end 2, peculiar nestingdifiiculties are encountered to economically produce these blanks. Ifthe blanks are not laid out closely contiguous, side by side, with oneconforming as closely as. possible to the contour of the next adjacentblank, as for example, when the wide ends l-of a group are arrangedparallel.

against the edge 5 of the sheet, this arrangement adds to the necessaryoverall widthpf the sheet and causes the offset ends 201' the blanks tofan apart and to be spaced away from the lower longitudinal edge 6,thereby causing more scrap Thus, in the usual rectangular mill sheet andwith such blank arrangement, it is obvious that whatever is saved at oneside of the sheet by abutting the wide ends of the blank with-the edge.5, will be lost at the opposite sideedge 5 and adjacent bottom edge 6 bythe kickup ends 2 being disposed to curve away from one corner of thesheet to result in more and more scrap being left at this corner as thenumber of blanks persheet is increased.- If alternate blanks be reversedin lengthwise direction to the others, the kickup ends 2 willengage thewiderends 4 areas and greater waste between the blanks, resulting ingreater widths of sheets required. Applicant has found that greatereconomy can be achieved by extending some of the blankslengthwise in thesame direction and juxtaposing the kickup ends 2 of the blanks on thesheet, so that the kickups nest closely within one another, as shown inthe drawing, which causestheir wideends to spread somewhat or fanout andmake allowance for their taper and with the major portion of thelengthwise edge of the first blank substantially parallel with thelengthwise edge 6 of. the sheet to reduce scrap-between the blanks. Thesucceeding blanks are arranged with their longitudinal edgessubstantially coinciding with the longitudinal edges of adjacent blanks.This arrangement disposes the transverse ends of the blanks in steppedrelationship, somewhat diagonally of the sheet and results in producingmore of these blanks per unit of weight, but which inevitably results inthe production of comparatively large scrap pieces S at both sides ofthe rectangular sheet. While this form. of nesting reduces scrap lossesbetween will require an excessive width of sheet, if the samedisposition of blanks is continued all the way across the width of thesheet.

This growth in the width of the sheet for a predetermined number ofblanks has again been reduced by an arrangement provided by applicant,which contemplates an end to end lengthwise reversal of some of theblanks after a predetermined number have been laid out to extend in onedirection as shown in the drawing. In other words, after four blankshave been laid out on the sheet in one direction, the next succeedinggroup of blanks are laid out in the reverse lengthwise direction, sothat the blanks will consume only the minimum amount of stock and willcut down on the width of sheet necessary for the production of apredetermined number of blanks. However, such increase in the number ofblanks per ton ofsheets requires the use of wider sheets which naturallyincreases the scrap loss S in a rectangular sheet asIthe.

number of blanks per sheet is increased.

With eight blanks laid out on the old form of rectangular sheet asillustrated in Fig. 2 of the drawing, and with applicants form ofdiagonal nesting employed with four blanks reversed end for end withrespect to the first group of four blanks, each pair of blanks wouldweigh 29.37 pounds of steel figured from the gross weight of the sheet,due to the loss of the scrap portions S and S at the side edges 5 of therectangular sheet. Such an arrangement would require the width of therectangular sheet to be 60%", which exceeds one of the premium costsheets of 60 inches. Consequently, with such rectangular sheets it ismore economical to only blank out six blanks from a single sheet andarrange them in av group of four, with a succeeding group of two blanksreversed end for end with respect to the first group of four, so thatthe minimum width required for the sheet to produce 6 blanks is 46%inches, making each pair of blanks weigh 29.8 pounds of the gross weightof the entire sheet. Such a sheet is usually of an inch stock,rectangular in shape, measuring 46% inches wide and 751inches long. Thisrectangular sheet will produce only six blanks with the best possiblenesting. Even with this form of nesting the blanks in groups on the oldform of rectangular mill sheets, there is considerable scrap loss at thetwo side edges 5 of the sheet represented by the areas marked S in Fig.2.

In order to avoid this scrap loss incidental in blanking all rectangularsheets, applicant proposed to the steel mills, the use of a rhomboidalsheet of steel 3 shown in Fig. 1, which was contrary to steel mill.practice and resulted in the invention of the new continuous diagonalshearing equipment disclosed in the Maddock and Fenton application,Serial No. 242,554 for Blanking apparatus filed November 26, .1938. Asno equipment existed in the steel mills for cutting such rhomboidalshaped sheets on any practical or commercial basis, thatv is to say, onany practical.

cost basis, the invention required the operation of entirely newautomatic equipment for shearing these specially shaped sheets on acontinuous strip mill to render it a. commercially feasible proposition.

With such rhomboidal shaped sheets economically produced at no more costthan the production of the old rectangular sheets, applicant proposed tonest the blanks B on such sheets so that a line drawn through the ends.of such blanks, would be very closely parallel to the inclined oppositeside edges of the rhomboidal sheet to entirely eliminate the large scrapareas S shown in Fig. 2. Thus, with the new form of sheet andarrangement of blanking shown in Fig. 1, it is possible to obtain eightof the same size sub-rail blanks from a slightly larger sheet measuring58% inches by 73 inches and with no scrap loss or waste S at the sidesof the sheet. For the amount of steel in this rhomboidal sheet 3 in Fig.1, each pair of the eight blanks requires only 28.37 pounds of the grossweight of the sheet, which represents a saving of 1.31 pounds per pairof blanks. In dollars and cents this results in a saving of .0327 centper pair of blanks, which, with the slight saving in the necessarypickling cost of the material brings the total saving to .0335 cent perpair of blanks over the six blank sheet measuring 46%, by 751%.

As another example of the savings effected in blanking full lengthautomobile side rails having a forward drop and a rear kickup, it wasnecessary before this invention to use a rectangular sheet measuring 50inches by 169% inches equal to pounds per rail. By using the rhomboidalsheet 3 and the method of nesting disclosed herein the dimensions of thesheet can be reduced to inches by 166% inches to obtain the same numberof side rail blanks,'which from the amount of steel in the sheet, makeseach rail require 44.75 pounds of steel for its production, therebyresulting in a saving of .0384 cent per pair of rail blanks includingthe incidental saving of .0009 cent in pickling costs. In

1 to the other two opposed parallel edges.

the case of some automobile frames requiring the use of severalrhomboidal sheets, it has been found that it is possible to save as muchas 10 cents per frame over the cost when rectangular sheets are used.

These savings are possible in a large degree because the stock is cut inthe new shape by the steel mill, since in the usual stock furnished, theloss becomes prevalent in the handsof the fabricator and only when themill sto'ck'is vcut up into multiple products and scrap is left over. Inother words, the usual rectangular sheet furnished by the mills cannotbe blanked and cut by the customer to advantage without material scraplosses. Scrap represents tonnage and since steel is sold by the ton,the-customer in every purchase of sheet steel, naturally pays for somethat he cannot use to advantage and must dispense with as scrap piecesand trimmings at a loss over the price paid for the steel from which theproducts are blanked.

Due to steel mill practice, setup, unusually heavy immovable equipment,and the fact that continuous high speed production of steel strip andsheet is requisite for lower steel prices, these mills have only beenable to cut and supply the usual rectangular sheets. .This practice hasbeen continued for many years and thepractice of blanking from theserectangular sheets has naturally followed and has been used by thefabricators for twenty or more years with no time used or proposed. Withthis practice continuing for so many years, without change, it neveroccurred to anyone prior to applicant how this waste could be avoided.

, The new rhomboidal shape of the sheet 3 is shown inFig. 1 withopposite pairs of edges parallel and with two of the opposite edges 1arranged at an angle other than at right angles In the specificillustration the angle the edges form at a pair of diagonal corners isapproximately 82% I degrees and at the other pair of diagonal corners isapproximately 97 /2 degrees. It will of course be understood that theangles of the rhombus can be varied to suit the particular job in hand.

Fig. 2 illustrates the usual rectangular sheet universally furnished bythe mills. The most economical nesting relation of the form of subrailblanks illustrated, which is possible in such sheets, is obtained in asheet measuring 46 inches by 72% inches, from which is obtained asstated before, only six sub-rails and a considerable waste of scrapmaterial at the two sides of the sheet. By making the sheets ofrhomboidal outline as shown in Fig, 1, and of very little larger size,namely 58% inches by 73% inches, and nesting the blanks as proposed byapplicant and as shown in both figures, eight of the same sized blankscan be obtained at a saving of .0327 cent per pair of blanks. Therhomboidal sheets are obtained by automatically cutting continuouslytraveling strip steel transversely and obliquely at predeterminedintervals. Hand cutting of such sheets would of course be entirely outof the question as it would add more expense and render the price to thefabricator prohibitive.

It is to be understood that nesting arrangements of the blanks otherthan those disclosed herein may be employed with blanks of other shapesand the scope of the claims is to be limited only by the state of theart.

I claim:

1. The steps in the method of producing an elongated narrow taperedmetal blankwith lateral co-planar ofisets, consisting of providing afiat sheet of metal of rhomboidal shape, and laying out an elongatedblank with its longitudinal axis arranged diagonally of said sheet,thereby causing the transverse end edges of the blank to be arrangedsubstantially parallel with the inclined edges of said sheet.

2. The steps in the method of producing elongated flat narrow taperedmetal blanks with lateral co-planar offsets, consisting of providing aflat sheet of metal of rhomboidal shape, and laying out a series oftapered elongated blanks with lateral co-planar offsets thereon in suchmanner that a line drawn substantially parallel with an inclined edge ofsaid sheet passes through the corresponding ends of all of said blanks.

3. The steps in the method of producing elongated flat narrow taperedmetal blanks with lateral co-planar offset-s consisting of providing aflat sheet of metal of rhomboidal shape, and

laying out a series of tapered elongated blanks with lateral co-planaroffsets thereon with the blanks arranged to obtain a greater number ofsaid blanks per ton of sheets than from rectangular sheets of the samesize and weight.

4. The steps in the method of producing elongated fiat narrow metalblanks with lateral coplanar offsets, consisting of providing a flatsheet of metal of rhomboidal shape, and cutting a series of taperedelongated blanks with lateral co-planar oifsets therefrom with thelongitudinal edges of the blanks substantially parallel with a pair ofopposite edges of the sheet, and the ends of all of the blanks beingarranged in stepped relation substantially parallel with the othertwoopposite edges of the sheet. 7

5. The steps in the method of producing elongated metal blanks withlateral co-planar offsets, consisting of providing a flat sheet of metalof rhomboidal shape, and cutting a series of tapered elongated blankswith lateral co-planar ofisets therefrom with the longitudinal edges ofthe blanks substantially parallel with a pair of parallel opposite edgesof the sheet, and the ends of all of the blanks being arranged ininclined stepped relation substantially parallel with the other oppositeinclined and parallel edges of the sheet.

6. The steps in the method of producing elongated tapered metal blankswith lateral co-planar offsets, consisting of providing a sheet of metalof rhomboidal shape, laying out a group of said blanks to extendlengthwise and adjacent the base of the rhombus, with their longitudinaledges substantially parallel with said base and with the ends of saidblanks arranged in stepped relation substantially parallel with theinclined side edges of the rhombus, and laying out a second group ofsaid blanks in the same manner adjacent the edge of the sheet oppositesaid base but in a reverse lengthwise direction and with their ends instepped relation arranged as a continuation of the first named group andparallel with the same inclined side edges of the rhombus, whereby theends of all blanks arranged at each inclined side edge of the sheet aredisposed on a line substantially parallel with said inclined side edges.

ROBERT H. MADDOCK.

